02 caravan strange heat problem on 2002 Dodge Grand Caravan

My 02 grand caravan heats up fine and the temp gauge moves up normally but as soon as I start to drive, the air from the blower cools down and the temperature gauge need drops back to cold. it takes a few minutes to cool down. when I stop, it slowly starts to heat up again. thermostat problem?

by in Pensacola, FL on December 29, 2008
2 answers 1 comment
ANSWER by on January 01, 2009
it sounds like a thermostat problem, How long does your car take to warm up if it just idles from a cold start. It should go from 30-40 degrees F to 180-190 degrees F within 4-5 minutes. This should be the middle of the gauge and that means the the heater should blow very warm at this point. If not then the thermostat is getting 'lazy'. It may even set a Check Engine Light for 'slow warm up'.
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COMMENT by on January 16, 2009
UPDATE - dandd - thanks for the answer. Before you responded, I removed the thermostat housing and sure enough, the thermostat was cracked in half! They must have cracked it when assembling the car, as it had never been changed before. Over time it must have eventually fatigued the metal and broke completely in two. I bought a new one for $12, some coolant for $14 and put it back together. It works fine now. CAUTION - Anyone attempting to replace the thermostat - be careful. It sits in a little recess and there are small metal "tabs" bent over it to keep it in place. these were very difficult to push back out of the way. We ended up having to grind them off completely to get the new one to fit.
ANSWER by on December 28, 2010
put a new thermostat in. It is an easy job and will fix your problem.